Letter weight estimator
Not sure how much your letter weighs? Estimate it from the envelope, page size, paper weight and number of sheets.
Answer a few questions about your letter and we'll estimate its weight in grams.
The envelope you're mailing in.
The size of the sheets inside.
Letter
Legal
A4
Printed on the ream (most office paper is 20 lb).
20 lb
75 gsm
24 lb
90 gsm
28 lb
105 gsm
32 lb
120 gsm
How many pages in your envelope.
Envelope plus 1 sheet of paper.
Estimates assume typical paper stock and a dry, empty envelope. Actual weight varies with paper, ink, inserts and envelope construction — weigh it if it is close to a postal limit (30 g or 50 g).
Got a weight? Find the postage and the cheapest stamp combination.
These are estimates for general guidance, not a substitute for a scale. Actual weight varies with paper, ink, inserts and envelope construction. Weigh your letter before mailing if it is close to a postal weight limit.
Skip the scale. Send it online.
No weighing, no stamps, no trip to the post office. Upload your PDF and we'll print, envelope, and mail your letter across Canada or abroad.
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April 2025
How letter weight is calculated
A letter's weight is just the envelope plus the paper inside. Here's what goes into the estimate.
Paper weight: pounds and gsm
The number on the ream (“20 lb” in North America) is the paper's basis weight. The rest of the world measures the same thing in grams per square metre (gsm). They convert directly: 20 lb is about 75 gsm, 24 lb about 90 gsm, 28 lb about 105 gsm. Most home and office paper is 20 lb / 75 gsm.
Why a sheet weighs about 4.5 g
A sheet's weight is its area times its gsm. A Letter sheet (8.5 x 11 in) of 20 lb paper works out to roughly 4.5 g. Legal sheets are bigger, so they weigh more (about 5.8 g); A4 is close to Letter at about 4.7 g. Switch to heavier paper and every sheet scales up in proportion.
The envelope counts too
An empty #10 business envelope is about 6 g; larger catalog envelopes (9 x 12, 10 x 13) run 18-22 g before anything goes inside. We add the envelope to your pages to get the total. These envelope weights are typical values (window film, self-seal gum and heavier stock all nudge them up) which is why we treat them as approximate.
When to reach for a scale
Postage steps up at 30 g and 50 g for standard letters. If your estimate lands near one of those limits, a kitchen or postal scale is worth a check: a single extra sheet can tip you into the next price band. Once you know the weight, the stamp calculator works out the exact postage and stamps. Or easier, send your letter online!